Androgenic alopecia (AGA) is the most common form of hair loss, affecting approximately 30 to 40 percent of adult men and women. The incidence is generally considered to be greater in males than females. In men, the condition is also called male-pattern baldness. Commonly treatments for androgenic alopecia include hair follicle transplants, topical therapies, and orally prescribed antiandrogens (J. L. Roberts, 1997). The hyperandrogenic stimulation that causes alopecia also produces other undesirable physiological symptoms including acne vulgaris, benign prostatic hyperplasia, female hirsutism, and seborrhea.
Early attempts to provide a chemotherapeutic agent to counter the undesirable results of hyperandrogeneticity resulted in the discovery of several steroidal antiandrogens having undesirable hormonal activities of their own. The principal mediator of androgenic activity in some target organs, e.g. the prostate, is 5α-dihydrotestosterone (DHT), formed locally in the target organ by the action of testosterone-5-α-reductase. Inhibitors of testosterone-5α-reductase will serve to prevent or lessen symptoms of hyperandrogenic stimulation in these organs (Gormley et al. U.S. Pat. No. 5,981,543, 1999 and Rasmusson et al. U.S. Pat. No. 4,377,584, 1983).
Minoxidil (6-(1-piperidinyl)-2,4-pyrimidinediamide 3 oxide) is a drug known for the treatment of AGA. Minoxidil is effective when delivered topically ar a concentration of about 0.01% to about 5%. The topical solution of Minoxidil is currently marketed as “Rogaine” having 2% minoxidil concentration in a solution of (60% v/v) propylene glycol, and water. Disadvantageously, clinical trials have shown that the topical application of a 2% monixidil solution to patients experiencing hair loss results stimulated dense hair regrowth in only less than about 5% of the patients and moderate hair regrowth in only about 30% of the patients (E. A. Olsen, et al., 1985; J. Roberts, 1987), S. Niemiee et al. U.S. Pat. No. 6,419,913 B1, 2002).
Finasteride is a synthetic androgen inhibitor currently marketed as PROSCAR® for the treatment of benign prostatic hyperplasia. It has also been marketed orally in low dosage form as PROPECIA® for the treatment of androgenic alopecia (AGA) (hair loss). Chemically, finasteride is (5α, 17β)-N-(1,1-dimethylethyl)-3-oxo-4-azaandrost-1-ene-17-carboxamide and is practically insoluble in water, and is soluble only in organic solvents such as ethanol and methanol. Finasteride is known to inhibit 5α-reductase type 2.
Although, finasteride is currently administered orally, it is not available topically as approved product for the treatment of AGA. The side effects as a result of the oral administration for finasteride include erectile dysfunction, impotence, low libido, gynecomestica, and facial hair growth.
Development of new lipid-based formulation is needed to improve oral and or transdermal delivery and reduce the toxicity associated with compositions such as finasteride and minoxidil.